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| author | Paul Walmsley <pwalmsley@nvidia.com> | 2013-12-18 05:02:14 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-02-09 13:39:26 +0100 |
| commit | c32fa99f0b4252633aa464e28d1cb925bd2a79df (patch) | |
| tree | 3f857effbb10d28785fa4d4cc8d0f2fbe1c1e7ba /include/asm-generic | |
| parent | 494479038d97f1b9f76fc633a360a681acdf035c (diff) | |
| download | linux-c32fa99f0b4252633aa464e28d1cb925bd2a79df.tar.gz | |
bitops: Fix signedness of compile-time hweight implementations
Enabling '-Wsign-compare' compiler warnings on code that includes
include/linux/bitops.h can generate the following warning:
In file included from include/linux/kernel.h:10:0,
from <random filename>:48:
include/linux/bitops.h: In function 'hweight_long':
include/linux/bitops.h:77:26: error: signed and unsigned type in conditional expression [-Werror=sign-compare]
(converted to an error with -Werror)
This is due to the use of the logical negation operator '!' in the
__const_hweight8 macro in include/asm-generic/bitops/const_hweight.h.
The use of that operator here results in a signed value.
Fix by explicitly casting the __const_hweight8 macro expansion to
'unsigned int'. While here, clean up several checkpatch.pl warnings.
Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1312180459580.30198@tamien
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/bitops/const_hweight.h | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/include/asm-generic/bitops/const_hweight.h b/include/asm-generic/bitops/const_hweight.h index fa2a50b7ee66..0a7e06623470 100644 --- a/include/asm-generic/bitops/const_hweight.h +++ b/include/asm-generic/bitops/const_hweight.h @@ -5,14 +5,15 @@ * Compile time versions of __arch_hweightN() */ #define __const_hweight8(w) \ - ( (!!((w) & (1ULL << 0))) + \ - (!!((w) & (1ULL << 1))) + \ - (!!((w) & (1ULL << 2))) + \ - (!!((w) & (1ULL << 3))) + \ - (!!((w) & (1ULL << 4))) + \ - (!!((w) & (1ULL << 5))) + \ - (!!((w) & (1ULL << 6))) + \ - (!!((w) & (1ULL << 7))) ) + ((unsigned int) \ + ((!!((w) & (1ULL << 0))) + \ + (!!((w) & (1ULL << 1))) + \ + (!!((w) & (1ULL << 2))) + \ + (!!((w) & (1ULL << 3))) + \ + (!!((w) & (1ULL << 4))) + \ + (!!((w) & (1ULL << 5))) + \ + (!!((w) & (1ULL << 6))) + \ + (!!((w) & (1ULL << 7))))) #define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 )) #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16)) |